X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fmain%2FMkIface.lhs;fp=ghc%2Fcompiler%2Fmain%2FMkIface.lhs;h=502547341d72e37f464dcc596552e06dad46a2a3;hb=4e84be0ce335385e094ba12d284855b510a36f53;hp=b4178dbfe0cee609a695a2b183065195f62bba43;hpb=fa654d6b16ecda7cc8cb780792ca10ec0e227555;p=ghc-hetmet.git

diff --git a/ghc/compiler/main/MkIface.lhs b/ghc/compiler/main/MkIface.lhs
index b4178db..5025473 100644
--- a/ghc/compiler/main/MkIface.lhs
+++ b/ghc/compiler/main/MkIface.lhs
@@ -55,7 +55,7 @@ import TyCon		( DataConDetails(..), tyConTyVars, tyConDataCons, tyConTheta,
 			  getSynTyConDefn, tyConGenInfo, tyConDataConDetails, tyConArity )
 import Class		( classExtraBigSig, classTyCon, DefMeth(..) )
 import FieldLabel	( fieldLabelType )
-import TcType		( tcSplitSigmaTy, tidyTopType, deNoteType, tyClsNamesOfDFunHead )
+import TcType		( tcSplitForAllTys, tcFunResultTy, tidyTopType, deNoteType, tyClsNamesOfDFunHead )
 import SrcLoc		( noSrcLoc )
 import Module		( Module, ModuleName, moduleNameFS, moduleName, isHomeModule,
 			  ModLocation(..), mkSysModuleNameFS, 
@@ -248,7 +248,13 @@ ifaceTyThing (AClass clas) = cls_decl
 	= ASSERT(sel_tyvars == clas_tyvars)
 	  ClassOpSig (getName sel_id) def_meth' (toHsType op_ty) noSrcLoc
 	where
-	  (sel_tyvars, _, op_ty) = tcSplitSigmaTy (idType sel_id)
+		-- Be careful when splitting the type, because of things
+		-- like  	class Foo a where
+		--		  op :: (?x :: String) => a -> a
+		-- and  	class Baz a where
+		--		  op :: (Ord a) => a -> a
+	  (sel_tyvars, rho_ty) = tcSplitForAllTys (idType sel_id)
+	  op_ty		       = tcFunResultTy rho_ty
 	  def_meth' = case def_meth of
 			 NoDefMeth  -> NoDefMeth
 			 GenDefMeth -> GenDefMeth